1. Field of the Invention
The present invention relates to power generation in general, and the collection of solar energy for heat or electrical generation in specific. More particularly, the invention comprises a mounting device for solar collectors which allows tracking of the sun in two dimensions, vertically and horizontally.
2. Description of the Prior Art
The use of solar energy has progressed from early use of sun heated rocks as a passive heat source to the highly efficient, active solar collectors of today. Even in the progression from early active solar collectors there have been great strides in more recent years. Early collectors were stationary, absorbing energy as the sun passed from first a peripheral position in the east to directly overhead and then to a peripheral position in the west. More recently, solar tracking devices have allowed collectors to track the sun's path, thus presenting a more direct face to the sun as it passes overhead, allowing the normally oblique rays of morning and evening to strike the collectors directly for additional solar gain.
U.S Pat. No. 4,566,432, issued to Isidore F. Sobczak, et, al., on Jan. 28, 1986; U.S. Pat. No. 4,535,961, issued to Isidore F. Sobczak, et. al., on Aug. 20, 1985; U.S. Pat. No. 4,463,749, issued to Isidore F. Sobczak, et. al., on Aug. 7, 1984; and U.S. Pat. No. 4,457,297, issued to Isidore F. Sobczak, et. al., on Jul. 3, 1984, present MODULAR SOLAR CONCENTRATORS and a LIGHTWEIGHT AZIMUTH/ELEVATION MOUNT, wherein the mount consists of a turret which can turn 360.degree. on its base for azimuth rotation with a lead screw providing horizontal mounted between the turret and the solar collector providing horizontal rotation. Sobczak provides a base for a single array of solar collectors while the present invention provides for mounting of multiple arrays.
U.S. Pat. No. 4,491,388, issued to Douglas E. Wood on Jan. 1, 1985, presents a SUPPORT CARRIAGE FOR A SOLAR CONCENTRATOR, similar to Sobczak in that a concentrator is mounted on a central pedestal about which it can rotate with horizontal rotation provided by a cable and track mechanism. Wood also provides a base for a single array of solar collectors while the present invention provides for mounting of multiple arrays.
U.S. Pat. No. 4,359,041, issued to Erlin E. Snodgrass on Nov. 16, 1982, presents a LIGHT ENERGY CONCENTRATING DEVICE, a collector composed of a plurality of segments, each rotatable about two axis to direct sunlight to a focal region. In Snodgrass, rotation is within the collector itself, as opposed to the present invention which is capable of rotating and tilting the entire collector to track the sun.
U.S. Pat. No. 4,301,321, issued to Frederick T. C. Bartels on Nov. 17, 1981, presents a TWO-AXIS FOCUSING ENERGY CONCENTRATOR, one of many solar concentrators which could be utilized with the present invention.
U.S. Pat. No. 4,252,107, issued to Richard H. Horton on Feb. 24, 1981, presents a SOLAR TRACKING CONCENTRATOR, a light weight, parabolic dish mounted to single pipe pedestal such that it is rotatable about a horizontal and vertical axis. Horton's pedestal will support a single concentrator, while the present invention can support any number of collectors desired.
U.S. Pat. No. 4,355,630, issued to Arthur Fattor on Oct. 26, 1982, presents a CONCENTRATING SOLAR COLLECTOR WITH TRACKING MULTIPURPOSE TARGETS, in which a focusing parabolic mirror concentrates solar on one or more positionable target(s) movable along a series of tracks. Fattor is positionable in one dimension for seasonable adjustment, while the present invention is positionable in two dimensions for continuous adjustment for tracking the sun throughout the day.
U.S. Pat. No. 4,172,739, issued to Devon Tassen on Oct. 30, 1979, presents a SUN TRACKER WITH DUAL AXIS DIURNAL MOVEMENT AND SEASONAL ADJUSTMENT. Tassen mounts a frame-work holding solar collectors on a rotatable, vertical shaft, allowing tracking of the sun about a vertical axis. Rotation of the vertical shaft is powered by a reversible, constant speed electric motor. Rotation about a horizontal axis is provided by a pair of cables and a guide means, counterbalanced by a spring mechanism, whereby rotation about the vertical axis causes one of the cables to wrap around the guide means, allowing the lower edge of the frame to be raised or lowered. Tassen supports a relatively small array of solar collectors while the present invention will support multiple arrays of collectors.
U.S. Pat. No. 4,476,853, issued to Clayton C. Arbogast on Oct. 16, 1984 presents a SOLAR ENERGY RECOVERY SYSTEM. With Arbogast, horizontal rotation is provided by a manually operated piston which elevates or lowers the upper end of a collector panel, rotating the panel around a lower pivot axis in accordance with a pivot plate indicating the proper angle for specified dates throughout the year. Vertical rotation is about pivotal connection members which connect the panel to both the manually operated piston and the lower pivot axis and is powered by a servo motor which can be controlled by a variety of different means.
U.S. Pat. No. 4,628,142, issued to Kenichi Hashizume on Dec. 9, 1986 presents SOLAR TRACKING MECHANISMS. Hashizume is designed for use in areas where conventional electrical power is not available and pivots only about the horizontal axis by means of a pair of sun sensors in the form of shape memory alloy (SMA) coils housed within compound parabolic concentrators (CMC) mounted along the opposite edges of the collector running parallel to the horizontal axis. As the SMA coil housed within the CMC aimed toward the sun heats, it expands allowing a connecting cable to relax. Simultaneously, the SMA coil shaded from the sun by its respective CMC contracts, drawing cable from a wire drum while the slack cable from the heated SMA coil winds onto a wire drum, thus turning the collector about its horizontal axis. In a second embodiment wherein the collectors are photo-voltaic cells, a DC motor powered by electric energy supplied by the cells moves the collector about its horizontal axis in a similar manner.
U.S. Pat. No. 4,832,001, issued to Stephen C. Baer on May 23, 1989, presents a LIGHTWEIGHT SOLAR PANEL SUPPORT. Baer is also designed for areas where conventional electrical power is not readily available and relies on sun sensors in the form of shaded, interconnected canisters provide the impetus for rotation. Baer's support is provided by a pair of A frame supports which are in compression supported by cable in tension. A array of collectors is supported by a pair of parallel cables separated by cross members and suspended between the A frame supports by a single cable. Rotation can be in either one or two dimensions, as the application dictates, and could again be provided by AD or DC motors should power be available.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.